/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.classfile.attribute.preverification;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;

/**
 * This StackMapFrame represents a "same frame" or a "same frame extended".
 *
 * @author Eric Lafortune
 * @noinspection PointlessArithmeticExpression
 */
public class SameZeroFrame extends StackMapFrame {
    /**
     * Creates an uninitialized SameZeroFrame.
     */
    public SameZeroFrame() {}

    /**
     * Creates a SameZeroFrame with the given tag.
     */
    public SameZeroFrame(int tag) {
        u2offsetDelta = tag - SAME_ZERO_FRAME;
    }

    // Implementations for StackMapFrame.

    public int getTag() {
        return u2offsetDelta < 64 ? SAME_ZERO_FRAME + u2offsetDelta : SAME_ZERO_FRAME_EXTENDED;
    }

    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset,
        StackMapFrameVisitor stackMapFrameVisitor) {
        stackMapFrameVisitor.visitSameZeroFrame(clazz, method, codeAttribute, offset, this);
    }

    // Implementations for Object.

    public String toString() {
        return super.toString() + "Var: ..., Stack: (empty)";
    }
}
